The Influence of Hard Water on 2,4-D Formulations for the Control of Dandelion

2020 ◽  
pp. 1-31
Author(s):  
Geoffrey P. Schortgen ◽  
Aaron J. Patton

The herbicide 2,4-D is used in a variety of cropping systems, especially in grasses since it is a selective postemergence broadleaf herbicide. However, the most common formulation (2,4-D dimethylamine) is antagonized when mixed in hard water. The objective of this research was to determine which formulations of 2,4-D or premixes of various formulations of synthetic auxin herbicides are subject to hard water antagonism. Formulations surveyed for hard water antagonism in the first experiment included 2,4-D dimethylamine, 2,4-D diethanolamine, 2,4-D monomethylamine, 2,4-D isopropylamine salt, 2,4-D choline salt, 2,4-D isooctyl ester, and 2,4-D ethylhexyl ester. Synthetic auxin formulation types in the second experiment included water-soluble, emulsifiable concentrates and emulsion-in-water. All formulations were mixed with both soft and hard water (600 mg CaCO3 L-1) and applied to dandelions to determine if antagonism occurred in hard water. Water-soluble (amine and choline) 2,4-D formulations were antagonized by hard water, but water-insoluble (ester) 2,4-D formulations were not antagonized. Similar results were found by formulation type with water-soluble synthetic auxin premixes antagonized but emulsifiable concentrates not antagonized. Further, water-soluble salt formulations were not antagonized when formulated in premixes with other synthetic auxin herbicides as an emulsion-in-water. This research demonstrates that all 2,4-D water-soluble formulations and water-soluble premixes with phenoxycarboxylic acid herbicides are subject to hard water antagonism. Formulations of 2,4-D containing emulsifying agents protect against antagonism by the water-insoluble nature of ingredients in their formulation.

2018 ◽  
Vol 32 (2) ◽  
pp. 182-189 ◽  
Author(s):  
Aaron J. Patton ◽  
Daniel V. Weisenberger ◽  
Geoff P. Schortgen

AbstractA population of buckhorn plantain with suspected resistance to 2,4-D was identified in central Indiana following 30 yr of 2,4-D–containing herbicide applications. Our objectives were to (1) confirm and quantify the level of herbicide resistance in the buckhorn plantain population using dose–response experiments and (2) find alternative herbicides that could be used to control this population. Greenhouse experiments were conducted to quantify the dose–response of resistant (R) and susceptible (S) biotypes of buckhorn plantain to both 2,4-D and triclopyr, two synthetic auxin herbicides from different chemical families. The R biotype was ≥6.2 times less sensitive to 2,4-D than the S biotype. The efficacy of triclopyr was similar on both the R and S biotypes of buckhorn plantain, suggesting the absence of cross-resistance to this herbicide. This is the first report of 2,4-D resistance in buckhorn plantain and the first report of 2,4-D resistance in turf. The resistance mechanism was limited to within a chemical family (phenoxycarboxylic acid) and did not occur across all WSSA Group 4 synthetic auxin herbicides, as the pyridinecarboxylic acid herbicides clopyralid and triclopyr and the arylpicolinate herbicide halauxifen-methyl provided control in our experiments.


2018 ◽  
Vol 32 (5) ◽  
pp. 597-602 ◽  
Author(s):  
Marcelo Zimmer ◽  
Bryan G. Young ◽  
William G. Johnson

AbstractSynthetic auxin herbicides such as 2,4-D and dicamba are often utilized to control broadleaf weeds in preplant burndown applications to soybean. Halauxifen-methyl is a new synthetic auxin herbicide for broadleaf weed control in preplant burndown applications to corn, cotton, and soybean at low use rates (5 g ae ha–1). Field experiments were conducted to evaluate efficacy and weed control spectrum of halauxifen-methyl applied alone and in mixtures with 2,4-D (560 g ae ha–1), dicamba (280 g ae ha–1), and glyphosate (560 g ae ha–1). Glyphosate-resistant (GR) horseweed was controlled with halauxifen-methyl applied alone (90% control) and in mixtures (87% to 97% control) 35 d after treatment (DAT). Common ragweed was controlled 93% with halauxifen-methyl applied alone and 91% to 97% in mixtures 35 DAT. Halauxifen-methyl applied alone resulted in poor giant ragweed control 21 DAT (73% control); however, mixtures of halauxifen-methyl with 2,4-D, dicamba, or glyphosate controlled giant ragweed (86% to 98% control). Halauxifen-methyl alone resulted in poor redroot pigweed control (62% control) 21 DAT; however, mixtures of halauxifen-methyl with dicamba, 2,4-D, or glyphosate controlled redroot pigweed (89% to 98% control). Halauxifen-methyl controls GR horseweed and common ragweed applied alone and in mixtures with other synthetic auxin herbicides and glyphosate. Furthermore, mixing 2,4-D or dicamba with halauxifen-methyl can increase the weed control spectrum in preplant burndown applications.


2020 ◽  
Vol 34 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Geoffrey P. Schortgen ◽  
Aaron J. Patton

AbstractHerbicides are an important tool in managing weeds in turf and agricultural production. One of the earliest selective herbicides, 2,4-D, is a weak acid herbicide used to control broadleaf weeds. Water-quality parameters, such as pH and hardness, influence the efficacy of weak acid herbicides. Greenhouse experiments were conducted to evaluate how varying water hardness level, spray solution storage time, and adjuvant inclusion affected broadleaf weed control by 2,4-D dimethylamine. The first experiment evaluated a range of water-hardness levels (from 0 to 600 mg calcium carbonate [CaCO3] L−1) on efficacy of 2,4-D dimethylamine applied at 1.60 kg ae ha−1 for dandelion and horseweed control. A second experiment evaluated dandelion control from spray solutions prepared 0, 1, 4, 24, and 72 h before application. Dandelion and horseweed control by 2,4-D dimethylamine was reduced when the CaCO3 level in water was at least 422 or at least 390 mg L−1, respectively. Hard-water antagonism was overcome by the addition of 20 g L−1 ammonium sulfate (AMS) into the mixture. When AMS was included in spray mixtures, no differences were observed at 600 mg CaCO3 L−1, compared with distilled water. Spray solution storage time did not influence dandelion control, regardless of water-hardness level or adjuvant inclusion. To prevent antagonism, applicators should use a water-conditioning agent such as AMS when applying 2,4-D dimethylamine in hard water.


ACS Omega ◽  
2018 ◽  
Vol 3 (7) ◽  
pp. 8365-8377 ◽  
Author(s):  
Vikas Kumar ◽  
Sandip B. Bharate ◽  
Ram A. Vishwakarma ◽  
Sonali S. Bharate

2016 ◽  
Vol 70 (11) ◽  
Author(s):  
Kateřina Hrdá ◽  
Jakub Opršal ◽  
Petr Knotek ◽  
Miloslav Pouzar ◽  
Milan Vlček

AbstractToxicity of zinc oxide nanoparticle (ZnO-NPs) powder and water soluble salt of Zn (ZnCl


2018 ◽  
Vol 28 (1) ◽  
pp. 6-9
Author(s):  
Carl W. Coburn ◽  
Albert T. Adjesiwor ◽  
Andrew R. Kniss

Creeping bellflower (Campanula rapunculoides) is a difficult to manage weed commonly found in turfgrass and residential areas. We evaluated the efficacy of selected postemergence herbicides (glyphosate, dicamba, clopyralid, quinclorac, and triclopyr) on greenhouse-grown creeping bellflower. The experiment was conducted in Jan. 2016 and repeated in Sept. 2016. Each herbicide was applied at five rates plus a nontreated control. Clopyralid caused greater creeping bellflower biomass reduction and mortality than the other herbicides investigated. The herbicide dose required to cause 50% mortality was lowest for clopyralid [86–138 g·ha−1 acid equivalent (a.e.)] compared with dicamba (221–536 g·ha−1 a.e.), glyphosate (196–678 g·ha−1 a.e.), triclopyr (236–782 g·ha−1 a.e.), and quinclorac (>3000 g·ha−1 a.e.). Clopyralid could be an effective herbicide for managing creeping bellflower, although it is currently not registered for use in many habitats where this plant is a problematic weed.


2014 ◽  
Vol 7 (2) ◽  
pp. 303-309 ◽  
Author(s):  
Brent A. Sellers ◽  
Sarah R. Lancaster ◽  
Kenneth A. Langeland

AbstractGreenhouse experiments were conducted to evaluate mile-a-minute response to selected herbicides. In the first experiment, mile-a-minute response was evaluated following the application of aminocyclopyrachlor, aminopyralid, fluroxypyr, glufosinate, glyphosate, imazamox, imazapic, metsulfuron, penoxsulam, and triclopyr. Applications of aminocyclopyrachlor, aminopyralid, fluroxypyr, glufosinate, glyphosate, and triclopyr all resulted in mile-a-minute control 70% or greater 8 wk after treatment (WAT). Mile-a-minute sensitivity to these six herbicides was further evaluated in a dose-response study. Although 90% growth reduction (GR90) values were determined for aminopyralid and glyphosate, statistically significant results were not obtained for aminocyclopyrachlor, fluroxypyr, glufosinate, and triclopyr. The results of these experiments suggest that glyphosate, as well as the synthetic auxin herbicides aminocyclopyrachlor, aminopyralid, fluroxypyr, and triclopyr, should be further evaluated for mile-a-minute control in south Florida.


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